Security Audit report: 4.2. Enhance encryption of values in memory.

c_micasad/cache/KeyValue.cs

@@ -132,7 +132,7 @@ namespace sscs.cache
 			return mLinkedKeys;
 		}
 
-
+	private DateTime m_dtEncryptTime = DateTime.Now;
     private DateTime m_created;
     public DateTime CreatedTime
     {
@@ -177,6 +177,8 @@ namespace sscs.cache
 
 		private byte[] EncryptValue(byte[] baValueClear)
 		{
+			// set encrypttime
+			m_dtEncryptTime = DateTime.Now;
 			return (XORValue(baValueClear));
 		}
 
@@ -191,19 +193,16 @@ namespace sscs.cache
 			return XORValue(m_value);
 		}
 
-        private byte[] XORValue(byte[] baInput)
-        {
-            
-            byte[] baOutput = new byte[baInput.Length];
-            Random rand = new Random((int)m_created.Ticks);
-            
-            for (int i=0; i<baInput.Length; i++)
-            {
-                baOutput[i] = (byte)((int)baInput[i] ^ rand.Next());
-            }        
-
-            return baOutput;
-        }
+		private byte[] XORValue(byte[] baInput)
+		{            			
+			byte[] baOutput = new byte[baInput.Length];			            
+			Random ranNum = new Random(this.Key.GetHashCode());
+			for (int i=0; i<baInput.Length; i++)
+			{								
+				baOutput[i] = (byte)((int)baInput[i] ^ ranNum.Next() ^ (~i) ^ m_dtEncryptTime.Ticks);
+			}        					
+			return baOutput;
+		}
 
 		public int GetValueType()
 		{